This research will study how basic behavioral processes such as learning, motivation, memory, attention and arousal change during the course of development from infancy to adulthood in mammals. The research will also analyze the relative importance of neurological versus interference variables as determinants of forgetting in infancy, and it will examine various mechanisms for maintaining learned responses that are normally forgotten during the course of development. Finally the research will study the ontogeny of excitation and inhibition and the ontogeny of physiological regulatory mechanisms.